This is a revised application for a Mentored Clinical Scientist Development Award. The purpose of this application is to acquire a theoretical statistical background and training in particular multivariate techniques, to be used to examine psychiatric symptom data in the members of families with a high rate of schizophrenia, to develop alternative classifications of affection status for use in genetic linkage studies. Support through this award would enable the applicant to develop a unique area of expertise within the field of psychiatric genetics, contributing to the long-term career goal of research independence. The contribution of genetic factors to the etiology of schizophrenia is well accepted. Multiple family studies have demonstrated elevated rates of schizophrenia and other psychiatric disorders within the families of schizophrenic probands. Numerous unsuccessful gene linkage studies of schizophrenia have been conducted, using traditional clinical diagnoses to define affection status. One possible factor contributing to these difficulties is that current clinical diagnoses do not accurately correspond to the patterns of symptoms seen in individuals from families with a high rate of schizophrenia. Analysis of the transmission patterns of individual symptom data, not only the overall diagnosis, may lead to a more useful definition of affection status for linkage studies.